The Department of Homeland Security recently planted several USB drives and CD-ROMs in a government facility parking lot to see how easy it would be to spread viruses, and 60% of workers plugged the drives and CDs into their computers accidentally executing the malware inside. To avoid the same mistake you should always open unkown discs and USB drives with a virtual machine.

Curiosity can get the best of us. If you're the kind of person who is dying to know what might be on a found drive, use a virtual machine with no permissions. That way no matter what lurks on the drive you can ensure that it won't spread through your system.